Scaffold Phase 1 hvac app — NewBook-driven room TRV heating scheduler

Ports the state machine, retry/backoff, and guest-override detection from
the retired homeassistant-newbook-heating-component, without depending on
Home Assistant. Backend (Fastify/pg) + frontend (React/Vite/TS) following
standard stack conventions; LXC 128 (127 was already taken by utilities).

MHI/Midea/Daikin/boiler drivers and the shared MQTT broker (LXC 104) are
later phases/infra, not included here.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

backend/package.json

@@ -0,0 +1,21 @@
+{
+  "name": "hnf-hvac-backend",
+  "version": "1.0.0",
+  "type": "module",
+  "scripts": {
+    "start": "node src/index.js",
+    "dev": "node --watch src/index.js"
+  },
+  "dependencies": {
+    "@fastify/cookie": "^9.4.0",
+    "@fastify/cors": "^9.0.1",
+    "@fastify/multipart": "^8.3.0",
+    "@fastify/static": "^7.0.4",
+    "fastify": "^4.28.1",
+    "jose": "^5.9.6",
+    "luxon": "^3.5.0",
+    "mqtt": "^5.10.3",
+    "pg": "^8.13.1",
+    "sharp": "^0.33.0"
+  }
+}